The present invention relates to novel phenylalkyl-2,3-dihydrobenzofurans and the corresponding dihydrobenzopyrans useful as anti-inflammatory agents. A group of benzyl-dihydrobenzofurans have been disclosed in U.S. Pat. No. 4,435,422 as effective diuretic agents. However, this patent does not disclose the novel compounds of the present invention, nor does it disclose the anti-inflammatory activity of the compounds of the present invention.
The novel compounds are effective in vitro as both leukotriene and prostaglandin synthesis inhibitors in the peritoneal macrophage assay and the polymorphonuclear leukocyte assay. They are also potent lipoxygenase inhibitors. Furthermore, they are found to be active in vivo in the topical mouse ear assay and the U.V. erythema assay as topical anti-inflammatory agents.
Recent studies demonstrated that macrophages and PMNs participate in the development and progression of chronic inflammatory diseases such as rheumatoid arthritis. During the progression of inflammatory conditions, there is generally an appearance and/or presence of macrophages and lymphocytes, especially macrophages and polymorphonuclear leukocytes. Macrophages are known to secrete various products in response to inflammatory stimuli. For example:
(1) Neutral proteinases--the destructive peptide bond cleaving enzyme which has been shown to be directly involved in rheumatoid cartilage destruction; and
(2) Prostaglandins (PG) (e.g., E.sub.2 and I.sub.2 by mouse peritoneal macrophages) and other arachidonic acid derivatives derived from both the cyclooxygenase and the lipoxygenase pathways.
These archidonic acid oxygenation products have been identified as the critical mediators of various acute inflammatory conditions.
Accordingly, pharmacological agents which are capable of inhibiting the formation of, the release of a mediator from, or the function of macrophages or polymorphonuclear leukocytes may also be effective agents in the treatment of rheumatoid arthritis, emphysema, bronchial inflammation, asthma, osteoarthritis, acute respiratory distress syndrome, shock syndromes, e.g., endotoxin shock syndrome, spondylitis, lupus, gout, psoriasis, pain, eye inflammation, and other inflammatory diseases.
Regarding the topical mouse ear assay, it has been previously established that classical nonsteroidal anti-inflammatory agents such as indomethacin and steroidal anti-inflammatory agents such as dexamethasone are active in this assay.
With respect to the U.V. erythema assay, it has been shown previously that the U.V. erythema condition is partially the result of a local release of prostaglandins derived oxidatively from arachidonic acid by the action of PG synthetases, e.g., cyclooxygenase. Therefore, pharmacological agents which inhibit the erythema are generally considered to be active topical anti-inflammatory agents.
Furthermore, anti-inflammatory agents which are not significantly systemically active are advantageous in the sense that they are not subject to the adverse effects, e.g., gastrointestinal ulcerations and bleeding that often plagued users of systemic NSAIDs (non-steroidal anti-inflammatory agents). Accordingly, an object of this invention is to provide novel phenylalkyldihydrobenzofuran derivatives and analogs as topical anti-inflammatory agents. These agents are useful in the treatment of dermal inflammatory conditions and prusitus such as sunburn, erythema, eczema, contact dermatitis, allergic dermatitis, psoriasis, and other skin diseases. They are also useful for topical application to prevent or treat peridontal diseases or to treat ocular inflammation.
Another object of this invention is to provide appropriate processes for the preparation of the subject novel compounds.
Still a further object of the present invention is to provide a pharmaceutically acceptable composition containing an effective amount of the active compound for the treatment of various inflammatory diseases especially those involving dermatological conditions.
Finally, it is the object of this invention to develop a method of treating inflammation especially dermal inflammation via the administration of a therapeutically effective amount of the novel compounds or pharmaceutically acceptable compositions thereof to a mammalian species in need of such treatment.